This invention relates to a method of making cadmium-based photovoltaic cells.
Previous processes for manufacturing this type of cell all suffer from high costs due to time consuming methods of production. Those methods are substantially the same as the methods used by the semiconductor industry and are restricted to batch production of discrete panels.
Vapor deposition or sublimation in a vacuum chamber is used to form the solar conversion layers of the cells. Both vapor deposition and sublimation are inherently slower than the method described below. In the existing methodology, of fabricating cadmium based PV solar cells, each layer is applied to a glass panel. At the end of the stacked thin film fabrication process, the indium conduction layer must be exposed by mechanical processing, since it was buried by succeeding layers of material.
Microwave heating has been used to melt materials within many industrial processes. I am not aware of its commercial use to form thin (100 nanometer or less) films on glass sheets or metal foils. One Japanese university research paper disclosed that microwave heating was used to melt cadmium telluride onto a copper plate.
Liquid nitrogen cooling is used commercially for many purposes, especially in biomedical and pharmaceutical production.
Using ultra-cooling simultaneously with high-temperature heating to control the development of the P-N junction between two semiconductors is not disclosed in the prior art nor is it found in commercial processes. Attempting to form a stacked thin-film PV cell with heat alone results in excessive mixing of the layers and little if any voltage potential between the layers.